To determine which of the given statements is true, let's analyze each option step by step.
### Step 1: Analyze Option A
**Statement:** Silicon exhibits a coordination number of 4 in its compounds.
- **Explanation:** Silicon (Si) typically forms four bonds in its compounds, which corresponds to a coordination number of 4. However, silicon can also expand its coordination number due to its ability to utilize d-orbitals, allowing it to accommodate more than four surrounding atoms in certain compounds. Therefore, this statement is not entirely accurate as it does not consider the possibility of higher coordination numbers.
**Hint:** Consider the bonding capabilities of silicon and its ability to utilize d-orbitals.
### Step 2: Analyze Option B
**Statement:** The bond energy of F2 is less than that of Cl2.
- **Explanation:** The bond energy of a molecule is influenced by the repulsion between lone pairs of electrons. In F2, the small size of fluorine leads to significant lone pair-lone pair repulsion, which weakens the bond. In contrast, Cl2 has larger atoms with less lone pair repulsion, resulting in a stronger bond. Thus, the bond energy of F2 is indeed less than that of Cl2.
**Hint:** Think about the effects of lone pair repulsion on bond strength in diatomic molecules.
### Step 3: Analyze Option C
**Statement:** Mn3+ oxidation state is more stable than Mn2+ in aqueous solution.
- **Explanation:** Manganese in the +2 oxidation state (Mn2+) is more stable in aqueous solution compared to the +3 oxidation state (Mn3+). This is due to the half-filled d-orbital configuration of Mn2+, which provides extra stability. Therefore, this statement is false.
**Hint:** Recall the stability of half-filled and fully filled d-orbitals in transition metals.
### Step 4: Analyze Option D
**Statement:** Elements of group 15 show only +3 and +5 oxidation states.
- **Explanation:** Group 15 elements (such as nitrogen, phosphorus, arsenic, etc.) can exhibit a range of oxidation states, including -3, +1, +3, and +5. For example, nitrogen can show oxidation states from -3 (in ammonia) to +5 (in nitric acid). Therefore, this statement is also false.
**Hint:** Review the oxidation states of group 15 elements and their common compounds.
### Conclusion
After analyzing all the options, we find that the only true statement is:
**True Statement:** The bond energy of F2 is less than that of Cl2 (Option B).
